1. Technical Field
The invention relates to a CCD type solid-state imaging device.
2. Description of the Related Art
A CCD type solid-state imaging device includes a plurality of photoelectric conversion elements, a plurality of vertical transfer sections (VCCD) that read out electric charges generated in each of the plurality of photoelectric conversion elements and that transfer the read charges in the vertical direction, a horizontal transfer section (HCCD) that transfers the electric charges transferred from each of the plurality of VCCD in the horizontal direction perpendicular to the vertical direction, and an output section that outputs an imaging signal corresponding to the electric charges transferred from the HCCD.
The VCCD includes a charge transfer channel formed in a silicon substrate and a plurality of electrodes formed above the charge transfer channel with a gate insulating film disposed therebetween. There is known a technique for improving the sensitivity by multiplying electric charges by means of avalanche multiplication when transferring electric charges through a charge transfer channel (for example, see Japanese Patent No. 2609363 and Japanese Patent No. 3483261).
In a method of multiplying electric charges during charge transfer as described above, noise charges and smear charges existing in the charge transfer channel are also multiplied. Accordingly, S/N (signal-to-noise ratio) is decreased.